NR2B-containing N-methyl-D-aspartate subtype glutamate receptors regulate the acute stress effect on hippocampal long-term potentiation/long-term depression in vivo

Behavioral stress facilitates long-term depression but impairs long-term potentiation in the hippocampus. Recent evidence in vitro demonstrates that the NIR2B-containing N-methyl-D-aspartate subtype glutamate receptor antagonist Ro25-6981 prevents the beh

N-methyl-D-aspartate receptor-dependent long-term potentiation in CA1 region affects synaptic expression of glutamate receptor subunits and associated proteins in the whole hippocampus

Long term potentiation in hippocampus, evoked by high-frequency stimulation, is mediated by two major glutamate receptor subtypes, alpha-amino-3-hydroxyl-5-methyl-4-isoxazole propionate receptors and N-methyl-D-aspartate receptors. Receptor subunit compos

Bell-shaped D-serine actions on hippocampal long-term depression and spatial memory retrieval

D-Serine, the endogenous coagonist of N-methyl-D-aspartate receptors (NMDARs), is considered to be an important gliotransmitter, and is essential for the induction of long-term potentiation. However, less is known about the role of D-serine in another for

Ketamine affects memory consolidation: Differential effects in T-maze and passive avoidance paradigms in mice

The effects of ketamine, an N-methyl-D-aspartate (NMDA) antagonist, on memory in animals have been limited to the sub-anesthetic dose given prior to training in previous studies. We evaluated the effects of post-training anesthetic doses of ketamine to se

Coupling between NMDA receptor and acid-sensing ion channel contributes to ischemic neuronal death

Acid-sensing ion channels (ASICs) composed of ASIC1a subunit exhibit a high Ca2+ permeability and play important roles in synaptic plasticity and acid-induced cell death. Here, we show that ischemia enhances ASIC currents through the phosphorylation at Ser478 and Ser479 of ASIC1a, leading to exacerbated ischemic cell death. The phosphorylation is catalyzed by Ca2+/calmodulin-dependent protein kinase II (CaMKII) activity, as a result of activation of NR2B-containing N-methyl-D-aspartate subtype of glutamate receptors (NMDARs) during ischemia. Furthermore, NR2B-specific antagonist, CaMKII inhibitor, or overexpression of mutated form of ASIC1a with Ser478 or Ser479 replaced by alanine (ASICla-S478A, ASIC1a-S479A) in cultured hippocampal neurons prevented ischemia-induced enhancement of ASIC currents, cytoplasmic Ca2+ elevation, as well as neuronal death. Thus, NMDAR-CaMKII cascade is functionally coupled to ASICs and contributes to acidotoxicity during ischemia. Specific blockade of NMDAR/CaMKII-ASIC coupling may reduce neuronal death after ischemia and other pathological conditions involving excessive glutamate release and acidosis.

Opioid Withdrawal for 4 Days Prevents Synaptic Depression Induced by Low Dose of Morphine or Naloxone in Rat Hippocampal CA1 Area In Vivo

The formation of memory is believed to depend on experience- or activity-dependent synaptic plasticity, which is exquisitely sensitive to psychological stress since inescapable stress impairs long-term potentiation (LTP) but facilitates long-term depression (LTD). Our recent studies demonstrated that 4 days of opioid withdrawal enables maximal extents of both hippocampal LTP and drug-reinforced behavior; while elevated-platform stress enables these phenomena at 18 h of opioid withdrawal. Here, we examined the effects of low dose of morphine (0.5 mg kg(-1), i.p.) or the opioid receptor antagonist naloxone (1 mg kg(-1), i.p.) on synaptic efficacy in the hippocampal CA1 region of anesthetized rats. A form of synaptic depression was induced by low dose of morphine or naloxone in rats after 18 h but not 4 days of opioid withdrawal. This synaptic depression was dependent on both N-methyl-D-aspartate receptor and synaptic activity, similar to the hippocampal long-term depression induced by low frequency stimulation. Elevated-platform stress given 2 h before experiment prevented the synaptic depression at 18 h of opioid withdrawal; in contrast, the glucocorticoid receptor (GR) antagonist RU38486 treatment (20 mg kg(-1), s.c., twice per day for first 3 days of withdrawal), or a high dose of morphine reexposure (15 mg kg(-1), s.c., 12 h before experiment), enabled the synaptic depression on 4 days of opioid withdrawal. This temporal shift of synaptic depression by stress or GR blockade supplements our previous findings of potentially correlated temporal shifts of LTP induction and drug-reinforced behavior during opioid withdrawal. Our results therefore support the idea that stress experience during opioid withdrawal may modify hippocampal synaptic plasticity and play important roles in drug-associated memory. (C) 2009 Wiley-Liss, Inc.

DE-71-induced apoptosis involving intracellular calcium and the Bax-mitochondria-caspase protease pathway in human neuroblastoma cells In vitro

Polybrominated diphenyl ethers (PBDEs) are used extensively as flame-retardants and are ubiquitous in the environment and in wildlife and human tissue. Recent studies have shown that PBDEs induce neurotoxic effects in vivo and apoptosis in vitro. However, the signaling mechanisms responsible for these events are still unclear. In this study, we investigated the action of a commercial mixture of PBDEs (pentabrominated diphenyl ether, DE-71) on a human neuroblastoma cell line, SK-N-SH. A cell viability test showed a dose-dependent increase in lactate dehydrogenase leakage and 3-(4,5-dimethylthia-zol-2-yl)-2,5-diphenyl-tetrazolium bromide reduction. Cell apoptosis was observed through morphological examination, and DNA degradation in the cell cycle and cell apoptosis were demonstrated using flow cytometry and DNA laddering. The formation of reactive oxygen species was not observed, but DE-71 was found to significantly induce caspase-3, -8, and -9 activity, which suggests that apoptosis is not induced by oxidative stress but via a caspase-dependent pathway. We further investigated the intracellular calcium ([Ca2+](i)) levels using flow cytometry and observed an increase in the intracellular Ca2+ concentration with a time-dependent trend. We also found that the N-methyl d-aspartate (NMDA) receptor antagonist MK801 (3 mu M) significantly reduced DE-71-induced cell apoptosis. The results of a Western blotting test demonstrated that DE-71 treatment increases the level of Bax translocation to the mitochondria in a dose-dependent fashion and stimulates the release of cytochrome c (Cyt c) from the mitochondria into the cytoplasm. Overall, our results indicate that DE-71 induces the apoptosis of ([Ca2+](i)) in SK-N-SH cells via Bax insertion, Cyt c release in the mitochondria, and the caspase activation pathway.

1.初级视觉皮层功能，GABA系统功能在衰老过程中的变化; 2.奖赏机制，极低频磁场的生物学效应研究

1 初级视觉皮层功能，GABA系统功能在衰老过程中的变化 本章首先对衰老过程中神经形态学和神经电生理学上的研究进行了综述，然后报道了作者的博士学位论文研究工作。实验采用神经电生理的手段，探讨初级视觉皮层（primary visual cortex；V1）功能，以及GABA（gamma-aminobutyric acid）系统功能在衰老过程中的变化。 实验1和2均采用单细胞记录技术，检测了中年猴V1细胞的方位选择性、方向选择性、自发放和最大反应，并与年轻和老年猴进行对比；比较了年轻和老年猴V1细胞的感受野外周抑制能力。在实验3中，我们记录了年轻和中年大鼠在给予GABA直接或间接的激动剂，戊巴比妥钠或氯胺酮{通过拮抗NMDA（N-methyl-D-aspartate）受体}后，其皮层的EEG（electroencephalogram）活动，并分析与年龄相关的差异。结果如下： 实验1：中年猴V1细胞的方向选择性和自发放介于年轻猴和老年猴之间，而方位选择性和最大反应与年龄之间没有相关性。 实验2：感受野外周区的最优刺激明显降低了年轻和老年猴具有高方位选择性细胞的比例。同时，年轻猴所有细胞，以及老年猴高方位选择性细胞具有较高的最大抑制比，与它们相比，老年猴无明显方位偏好细胞的最大抑制比显著降低； 实验3：戊巴比妥钠注射后，在年轻和中年大鼠上，alpha (8-12 Hz) 和beta (12-20 Hz) 频段EEG功率增加，theta (4-8 Hz) 功率减少，这些变化在中年大鼠上较为明显。氯胺酮注射后，中年大鼠theta功率比年轻大鼠具有更大幅度的降低。 我们的结果表明，视觉皮层功能的下调在衰老早期就已发生，其机制可能与抑制系统功能普遍降低有关. 2 奖赏机制，极低频磁场的生物学效应研究 本章首先对自然奖赏和药物成瘾机制、极低频磁场生物学效应，以及极低频磁场对奖赏系统的影响进行了综述，然后报道了作者的博士论文研究工作。实验目的是探讨大鼠眶额叶皮质（orbitofrontal cortex；OFC）活动与食物奖赏刺激的相关性，以及极低频磁场对小鼠空间认知能力的影响。 实验1采用EEG记录技术，检测了大鼠OFC在食物奖赏和渴求过程中EEG各频段的功率变化。在实验2中，使用了一种探索型Y-迷宫实验范式，它仅依赖于啮齿类动物天生的探索欲望，避免了奖赏效应的干扰，利用此新型迷宫，我们检测了25和50 Hz磁场对小鼠空间识别记忆能力的影响。其结果如下： 实验1：大鼠OFC的delta频段（2-4 Hz）EEG活动与食物刺激显著相关，其相对功率在食物渴求时下降，在食物奖赏时升高。 实验2：与短时照射相比，长时的50 Hz磁场照射降低了小鼠对新异臂的探索能力，而25和50 Hz磁场暴露都不影响小鼠的活动力。 本研究表明，食物奖赏与OFC的delta频段EEG活动密切相关，而我们以前发现，大鼠和猴OFC的gamma（20-100 Hz）活动与吗啡成瘾相关，提示了OFC在自然奖赏和药物成瘾中具有不同的作用；另外，本实验首次证明，极低频磁场损害了小鼠不依赖于奖赏系统的空间认知能力，而我们先前发现，极低频磁场可以强化吗啡诱导的条件化位置偏好，从而说明极低频磁场对吗啡成瘾具有独特的生物学效应。

NMDA受体NR1亚单位基因与精神分裂症的连锁分析

目的 了解N-甲基-D-天冬氨酸(NMDA)受体NR1亚单位基因与精神分裂症的连锁关系.方法 选取NR1亚单位基因所在区域的2个微卫星标记D9s1838和D9s1826,对94个符合美国精神障碍诊断与统计手册第4版精神分裂症诊断标准(DSM-Ⅳ)的中国汉族精神分裂症受累同胞对及家系成员共376个个体作基因分型,其中男性194名,女性182名.采用美国国立精神卫生研究所(NIMH)制订的《遗传研究诊断问卷》(DIGS),对家系成员躯体和精神状况进行评定;采用NIMH制订的《遗传研究家族问卷》(FIGS)了解家系结构.选用GENEHUNTER 2.1软件对分型资料进行非参数连锁分析.结果 两点、多点非参数分析最大LOD值均位于D9s1826,分别为1.70(P=0.050),2.08(P=0.015),两者均大于验证性连锁阈值1.2.结论 NR1基因区域微卫星标记与精神分裂症存在验证性连锁关系,提示NR1基因可能为精神分裂症的易感基因之一.

四种药用植物的化学成分及芍药苷的微生物转化研究

本学位论文共有5章。第一章报道白芍的化学成分及芍药苷的微生物转化研究成果；第二章报道天山雪莲的化学成分研究；第三章报道两面针的化学成分研究；第四章报道通关藤的化学成分研究成果；第五章概述了花椒属植物中最近十年报道的新化合物及药理研究情况。 在第1章的第一部分报道了白芍（Paeonia lactiflora Pall.）的化学成分。我们采用正、反相硅胶柱层析等各种分离方法，从白芍的干燥根中共分离出14个化合物，其中1个为新化合物，其结构通过波谱分析证实为没食子酰白芍苷，另外还有2个为首次从该植物中分离得到。第二部分报道了芍药苷的微生物转化生产芍药苷代谢素-I的研究，从15株厌氧菌中筛选出10株有转化活性的菌株，其中短乳杆菌Lactobacillus brevis AS1.12的转化活性最好，对其转化条件进行了初步的筛选，确定了相对合理的转化工艺。 在第2章报道了天山雪莲（Saussurea involucrate Kar.et Kir.）全草乙醇提取物化学成分的分离纯化和结构鉴定。通过正、反相硅胶柱层析等分离纯化和MS、NMR等波谱解析，共分离鉴定了28个化合物，结构类型分属于黄酮、倍半萜和木脂素等，其中2个新倍半萜化合物的结构分别表征为6α-羟基云木香酸6-β-D-吡喃葡萄糖苷和11βH-11,13-二氢去氢云木香内酯8α-O-(6′-乙酰)-β-D-吡喃葡萄糖苷。 第3章报道了两面针（Zanthoxylum nitidum （Roxb.）DC.）干燥根的乙醇提取物化学成分的分离纯化和结构鉴定。通过正、反相硅胶柱层析等分离纯化和MS、NMR等波谱解析以及X-射线单晶衍射，共分离鉴定了16个生物碱，结构类型分属于苯并啡啶类、喹啉类和阿朴啡类等，其中2个新苯并啡啶类生物碱的结构分别表征为二聚双氢两面针碱和丙酮基双氢崖定椒碱。 第4章报道了通关藤（Marsdenia tenacissima (Roxb.) Wight et Arn.）水提取物化学成分的分离纯化和结构鉴定。通过正、反相硅胶柱层析等分离纯化和MS、NMR等波谱解析以及X-射线单晶衍射，共分离鉴定了14个化合物，结构类型均属于C21多羟基甾醇，其中4个新化合物tenacigenoside A, tenacigenoside B, tenacigenoside C和tenacigenoside D的结构分别表征为3-O-6-deoxy-3-O-methyl-β-D-allopyranosyl-(1→4)-β-D-oleandropyranosyl-17β-tenacigenin B (62), 3-O-2,6- dideoxy-4-O-methyl-D-lyxo-hexopyranosly-11α-O- methylbutyryl-12β-O-acetyl-tenacigenin B (63), 3-O-6-deoxy-3-O-methyl-β-D- allopyranosyl-(1→4)-β-D-oleandropyranosyl-11α-O-tigloyl-tenacigenin C (64)和3-O-6-deoxy-3-O-methyl-β-D-allopyranosyl-(1→4)-β-D-oleandropyranosyl-11α-O-2- methylbutyryl-tenacigenin C (65)。 第5章概述了花椒属植物的化学成分及药理活性研究进展。 This dissertation consists of 5 chapters. The first chapter elaborate the phytochemical investigation of Paeonia lactiflora Pall., and microbial transformation of paeoniforin. The second, third and four chapters elaborate the phytochemical investigation of Saussurea involucrate Kar.et Kir., Zanthoxylum nitidum (Roxb.) DC. and Marsdenia tenacissima (Roxb.) Wight et Arn., respectively. Chapter 5 is a review on chemical constituents and bioactivities of Zanthoxylum species. The part one of chapter 1 focus on the isolation and identification of chemical constituents from P. lactiflora. Fourteen compounds were isolated from the roots of P. lactiflora by repeat column chromatography over normal and reversed phase silica gel. Among them, one is a new compound and the structure was suggested as galloyl-albiflorin by spectral evidence. In addition, two compounds were firstly reported in this plant. The part 2 is about microbial transformation of paeoniforin. Chapters 2, 3 and 4 were isolations and identifications of chemical constituents from S. involucrate, Z. nitidum and M. tenacissima, respectively. From the aerial parts of S. involucrate, 28 compounds including 7 flavonoids and 13 sesquiterpenoids were isolated and identified. Among them, 2 new compounds were characterized as 6α-hydroxycostic acid 6-β-D-glucoside and 11βH-11,13-dihydrodehydro- costuslactone 8α-O-(6'-acetyl)-β-D-glucoside, respectively, by means of spectroscopic analysis. Otherwise, 11 ones were firstly reported from this plant. The third chapter is about the phytochemical investigation of Z. nitidum. Sixteen compounds were isolated and identified. Among them, 2 new benzophenanthridine alkaloids were characterized as 8-acetonyldihydrofagaridine and 1,3-bis(8-dihydronitidinyl)-acetone by spectroscopic analysis. The fourth chapter is about the phytochemical investigation of M. tenacissima. Fourteen compounds were isolated and identified. Among them, 4 new compounds, tenacigenosides A~D, were characterized as 3-O-6-deoxy-3-O-methyl-β-D-allopyranosyl-(1→4)-β-D-oleandropyranosyl-17β- tenacigenin B, 3-O-2,6-dideoxy-4-O-methyl-D-lyxo-hexopyranosly-11α-O-methyl butyryl-12β-O-acetyl-tenacigenin B, 3-O-6-deoxy-3-O-methyl-β-D-allopyranosyl- (1→4)-β-D-oleandropyranosyl-11α-O-tigloyl-tenacigenin C, and 3-O-6-deoxy-3-O- methyl-β-D-allopyranosyl-(1→4)-β-D-oleandropyranosyl-11α-O-2-methylbutyryl- tenacigenin C. Chapter 5 is a review on recent progress in bioactive constituents from plants of Zanthoxylum species.

Autophobic Dewetting of a Poly(methyl methacrylate) Thin Film on a Silicon Wafer Treated in Good Solvent Vapor

The wettability of thin poly(methyl methacrylate) (PMMA) films on a silicon wafer with a native oxide layer exposed to solvent vapors is dependent on the solvent properties. In the nonsolvent vapor, the film spread on the substrate with some protrusions generated on the film surface. In the good solvent vapor, dewetting happened. A new interface formed between the anchored PMMA chains and the swollen upper part of the film. Entropy effects caused the upper movable chains to dewet on the anchored chains. The rim instability depended on the surface tension of solvent (i.e., the finger was generated in acetone vapor (gamma(acetone) = 24 mN/m), not in dioxane vapor (gamma(dioxane) = 33 mN/m)). The spacing (lambda) that grew as an exponential function of film thickness h scaled as similar to h(1.31) whereas the mean size (D) of the resulting droplets grew linearly with h.